Coxsackieviruses have been implicated in a number of different human diseases, including acute and chronic myocarditis, viral-induced insulin-dependent diabetes mellitus (IDDM), pancreatitis, chronic inflammatory myopathy, and chronic fatigue syndrome. The proposed research will examine the mechanisms of persistence in Coxsackievirus B3 (CVB3) infected mice, using a recombinant virus expressing the enhanced green fluorescent protein (eGFP). Our laboratory has established a solid foundation of molecular and immunological techniques and reagents from previous studies of CVB3 persistence and pathogenesis. Preliminary studies with recombinant eGFP-CVB3 indicate that a certain population of Hela RW cells in culture cannot support a productive infection, including quiescent cells (G0) and cells blocked at the G2/M phase of the cell cycle. The following experiments will test the hypothesis that persistence of CVB3 in mice may rely on infection of quiescent cells incapable of supporting viral replication; and that a subsequent change in the cell-cycle status may lead to virus reactivation and further viral/immune mediated pathology (including myocarditis) in the host. SPECIFIC AIMS: 1. To examine the stability of persistent or latent CVB3 RNA. Quiescent cells infected with eGFP-CVB3 and maintained in serum free media without passage will be monitored at multiple time points for viral replication (plaque assay) and for stability of viral RNA (RT-PCR). Virus rescue will be observed (GFP, RT-PCR, and plaque assay) after cell stimulation with 10 % FBS. 2. To investigate what factors or stimuli may be involved in reactivation of CVB3. Transgenic mice expressing SV40 T antigen in cardiac tissues will be characterized for greater pathogenesis following infection with eGFP-CVB3 by histology and GFP fluorescence. Stimulated PBLs from persistently infected mice will be examined for CVB3 reactivation by GFP expression.